Liquid crystal display device and manufacturing method thereof

ABSTRACT

A liquid crystal display device include a pair of substrates with liquid crystal material therebetween, a plurality of first spacers formed on one of the pair of substrates, and a second spacer formed on the one of the pair of substrates and arranged to surround the plurality of first spacers in plan view. The first spacer and the second spacer and are made of resin and are not made from the liquid crystal material. Further, a distance from the one of the pair of substrates to a top surface of the first spacers is smaller than a distance from the one of the pair of substrates to a top surface of the second spacer.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.10/636,559, filed Aug. 8, 2003, now U.S. Pat. No. 6,956,636, thecontents of which are incorporated herein by reference.

BACKGROUND OF THE INVENTION

The present invention relates to a liquid crystal display device and amethod of manufacturing the same; and, in particular, the inventionrelates to a liquid crystal display device having a configuration inwhich a liquid crystal materials maintained by a seal material on onesubstrate and is enclosed by overlaying another substrate thereon, and amethod of manufacture thereof.

A liquid crystal display device is constituted by a pair of substratesprovided opposite to each other in spaced relationship with a liquidcrystal material interposed therebetween, and electrodes are provided onat least one of the substrates to form a multiplicity of pixels providedin the direction in which the liquid crystal material spreads. Theliquid crystal material is enclosed within a space between thesubstrates by a seal material that also secures one of the substrates tothe other substrate.

Referring to the enclosure of the liquid crystal material in such acase, in a typical configuration, the liquid crystal material maintainedby the seal material on one of the substrates is enclosed by overlayingthe other substrate on the one substrate. Specifically, a configurationis known in which the seal material is formed on one of the substrates;the liquid crystal material is dispensed in an appropriate amount in anarea surrounded by the seal material; and the other substrate isthereafter overlaid and secured to the seal material (seeJP-A-2001-337335).

A liquid crystal display device having such a configuration makes itpossible to provide a liquid crystal display panel with a size greaterthan that achievable with a method in which a cell is formed withsubstrates and a seal material, and in which a liquid crystal materialis introduced through a liquid crystal sealing port formed in a part ofthe seal material, for example.

SUMMARY OF THE INVENTION

In the case of a liquid crystal display device having such aconfiguration, however, it is difficult to control the appropriateamount of the liquid crystal material when it is dispensed, whichfrequently results in an outflow of a redundant portion of the liquidcrystal material beyond the seal material when the other substrate isoverlaid thereon.

In this case, the liquid crystal material that has flowed out beyond theseal material is susceptible to contamination for some reason; thecontamination spreads also in the liquid crystal material within theseal material; and the contamination that has thus spread can result inthe problem of reduction in the display quality.

For example, when a thermosetting material having a high bondingstrength is used as the seal material, the liquid crystal material maybe contaminated to such a degree that irregularities of luminance canoccur when it contacts the seal material that has not set yet. Thisholds true for a photo-setting seal material.

The invention has been conceived under such circumstances, and it is anobject of the present invention to provide a liquid crystal displaydevice in which contamination of the liquid crystal material does notspread, and a method of manufacturing the same.

Typical features of the invention disclosed in the present applicationwill now be briefly described below.

(1) A liquid crystal display device according to the present inventionis characterized in that it has a seal material for isolating a liquidcrystal material from the outside, which seal material is providedbetween substrates that are disposed opposite to each other with theliquid crystal material interposed therebetween, the seal material beingformed as a portion that encloses the liquid crystal material in a partthereof or an annular pattern having no trace of the same, a firstrib-like supporting strut provided inside the seal material and betweenthe substrates to prevent the liquid crystal material from contactingthe seal material, and a second rib-like supporting strut that, incombination with the first rib-like supporting strut, forms a passageinto which the liquid crystal material flows out from an opening servingas an exit formed in the first rib-like supporting strut.

(2) In a method of manufacturing a liquid crystal display deviceaccording to the present invention, a liquid crystal material isdispensed into an area surrounded by a seal material on one substrate onwhich the seal material is formed and in which another substrate isoverlaid in a face-to-face relationship, the method being characterizedin that it includes the steps of forming a first rib-like supportingstrut inside the seal material on the substrate, the first supportingstrut being substantially concentric with the seal material and havingan opening in a part thereof, forming a second rib-like supporting strutoutside the first rib-like supporting strut, the second supporting strutbeing formed with a length to sufficiently extend across the opening,and dispensing the liquid crystal material within an area surrounded bythe first rib-like supporting strut.

(3) For example, a liquid crystal display device according to theinvention is characterized in that it has a seal material for isolatinga liquid crystal material from the outside, which seal material isprovided between substrates that are disposed opposite to each otherwith the liquid crystal material interposed therebetween, a rib-likesupporting strut provided inside the seal material and between thesubstrates to prevent the liquid crystal material from contacting theseal material, and strut-like spacers positioned at a multiplicity ofpixels formed in an area surrounded by the rib-like supporting strut,wherein the strut-like spacers and the rib-like supporting strut areformed such that the height of the top of the rib-like supporting strutabove the top surface of the substrate to which it is secured is greaterthan the height of the top of the strut-like spacers, and wherein a gapadjusting layer is formed on a liquid crystal side of the othersubstrate provided opposite to the above-mentioned substrate at least ina region that is opposite to the strut-like spacers.

(4) For example, a liquid crystal display device has first and secondsubstrates with a liquid crystal layer disposed therebetween; sealmaterial formed on the first substrate and enclosing a space between thefirst substrate and the second substrate; and means to maintain theliquid crystal material within the space in such a way as to avoidcontact with the seal material.

(5) For example, a liquid crystal display device has first and secondsubstrates with a liquid crystal layer disposed therebetween; sealmaterial formed on the first substrate and enclosing a space between thefirst substrate and the second substrate; and means to control the gapbetween the first substrate and the second substrate by adjusting thearea filled with the liquid crystal material.

The invention is not limited to the above-described configurations, andvarious modifications may be made within the scope of the technicalteaching of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a diagrammatic plan view and FIG. 1B is a sectional viewtaken along line b-b in FIG. 1A, showing an embodiment of a liquidcrystal display device according to the invention;

FIG. 2 is a diagrammatic plan view which illustrates an advantage of theliquid crystal display device according to the invention;

FIG. 3 is a diagrammatic plan view of another embodiment of a liquidcrystal display device according to the invention;

FIGS. 4A to 4D are diagrams which constitute a flow chart showing anembodiment of a method of manufacturing a liquid crystal display deviceaccording to the invention;

FIG. 5 is a diagrammatic plan view of another embodiment of a liquidcrystal display device according to the invention;

FIG. 6 is a diagrammatic plan view of another embodiment of a liquidcrystal display device according to the invention;

FIG. 7 is a diagrammatic plan view of another embodiment of a liquidcrystal display device according to the invention;

FIG. 8 is a diagrammatic plan view of another embodiment of a liquidcrystal display device according to the invention;

FIG. 9 is a diagrammatic plan view of another embodiment of a liquidcrystal display device according to the invention;

FIG. 10 is a diagrammatic plan view of another embodiment of a liquidcrystal display device according to the invention;

FIG. 11A is a diagrammatic plan view and FIG. 11B is a sectional viewtaken along line b-b in FIG. 11A, showing another embodiment of a liquidcrystal display device according to the invention;

FIG. 12 is a sectional view of another embodiment of a liquid crystaldisplay device according to the invention;

FIG. 13 is a sectional view of another embodiment of a liquid crystaldisplay device according to the invention;

FIG. 14 is a sectional view of another embodiment of a liquid crystaldisplay device according to the invention;

FIG. 15 is a sectional view of another embodiment of a liquid crystaldisplay device according to the invention;

FIG. 16 is a diagrammatic plan view of another embodiment of a liquidcrystal display device according to the invention;

FIG. 17 is a diagrammatic plan view of another embodiment of a liquidcrystal display device according to the invention; and

FIG. 18A is a diagrammatic plan view which shows a general configurationof an embodiment of a liquid crystal display device according to theinvention, and FIG. 18B is an equivalent circuit diagram of a pixelshown in the area B in FIG. 18A.

DETAILED DESCRIPTION

Embodiments of a liquid crystal display device according to the presentinvention will now be described with reference to the drawings.

First Embodiment

(General Configuration)

FIG. 18A is a diagrammatic plan view showing the general configurationof an embodiment of a liquid crystal display device according to theinvention. FIG. 18A shows a configuration consisting of an array ofpixels in the form of an equivalent circuit diagram. FIG. 18B shows anexample of an equivalent circuit of a single pixel.

First, there is a pair of transparent substrates SUB1 and SUB2 that areprovided opposite to each other with a liquid crystal materialinterposed therebetween, and the liquid crystal material is enclosedwith a seal material SL that also secures the transparent substrate SUB2to the other substrate SUB1.

On a surface of the liquid crystal side of the transparent substrateSUB1, the periphery of which is surrounded by the seal material SL,there are gate signal lines GL that extend in an x-direction and aredisposed in parallel with each other in a y-direction and drain signallines DL that extend in the y-direction and are disposed in parallelwith each other in the x-direction. A region that is surrounded byadjacent gate signal lines GL and adjacent drain signal lines DLconstitutes a pixel region, and a plurality of such pixel regions in theform of a matrix array constitutes a liquid crystal display area AR.

In each of the pixel regions that are in parallel with each other in thex-direction, a common counter voltage signal line CL is formed such thatit is routed through the pixel regions. The counter voltage signal linesCL serve as signal lines for supplying a voltage to be used as areference for a video signal to a counter electrode CT of each pixelregion.

Each pixel region is formed with a thin film transistor TFT that isoperated by a scan signal received from a gate signal line GL located onone side thereof and a pixel electrode PX to which a video signal issupplied from a drain signal line DL located on one side thereof via thethin film transistor TFT.

An electric field is generated between the pixel electrode PX and thecounter electrode CT that is connected to the counter voltage signalline CL, and the light transmittance of the liquid crystal material iscontrolled by the electric field.

One end of each of the gate signal lines GL is extended beyond the sealmaterial SL, and the extended end constitutes a terminal to which anoutput terminal of a scan signal driving circuit V is connected. Asignal from a printed circuit board (not shown) provided outside theliquid crystal display panel is input to an input terminal of the scansignal driving circuit V. The scan signal driving circuit V isconstituted by a plurality of semiconductor devices, and a plurality ofgate signal lines GL, which are disposed adjacent to each other, aregrouped together, one of the semiconductor devices being allocated toeach of such groups.

Similarly, one end of each of the drain signal lines DL is extendedbeyond the seal material SL, and the extended end constitutes a terminalto which an output terminal of a video signal driving circuit He isconnected. A signal from a printed circuit board (not shown) providedoutside the liquid crystal display panel is input to an input terminalof the video signal driving circuit He. The video signal driving circuitHe is also constituted by a plurality of semiconductor devices, and aplurality of drain signal lines DL, which are disposed adjacent to eachother, are grouped together, one of the semiconductor devices beingallocated to each of such groups.

The counter voltage signal lines CL are connected together at the rightend, as seen in the figure, and the connecting line is extended beyondthe seal material SL to form a terminal CLT at the extended end thereof.The voltage to serve as a reference for a video signal is suppliedthrough the terminal CLT.

The gate signal lines GL are sequentially selected one at a time by ascan signal received from the scan signal driving circuit V. A videosignal is supplied from the video signal driving circuit He to each ofthe drain signal lines DL in accordance with the timing at which thegate signal lines GL are selected.

While the scan signal driving circuit V and the video signal drivingcircuit He in the above-described embodiment are illustrated assemiconductor devices mounted on the transparent substrate SUB1, theymay be so-called tape carrier type semiconductor devices that areconnected between the transparent substrate SUB1 and the printed circuitboards. Further, when semiconductor layers of the thin film transistorsTFT are constituted by polycrystalline silicon (p-Si), the semiconductordevices made of polycrystalline silicon may be formed on a surface ofthe transparent substrate SUB1 along with a wiring layer.

While the pixel electrode PX and the counter electrode CT of a pixel areprovided in parallel with the liquid crystal layer in theabove-described embodiment, they may be formed so as to oppose eachother in the vertical direction with the liquid crystal materialinterposed therebetween, i.e., the counter electrode may be formed onthe transparent substrate SUB2. In this case, both of the pixelelectrode PX and the counter electrode CT are constituted by atranslucent conductive film, such as an ITO (indium tin oxide) film, toallow light to pass through the electrodes.

(Configuration of the Seal Material and the Neighborhood)

FIG. 1A is a diagram showing the seal material SL and the neighborhoodthereof in an embodiment of the present invention. FIG. 1A is a planview, and FIG. 1B is a sectional view taken along the line b-b in FIG.1A.

In FIG. 1A, the seal material SL is formed on either of the transparentsubstrate SUB1 and the transparent substrate SUB2 using a dispenser, forexample; the liquid crystal material is dispensed to a region inside theseal material SL; the other substrate is placed on the seal material SLopposite to the first substrate after the liquid crystal material isfilled to cover the liquid crystal display area AR sufficiently; and thesecond substrate is secured to the seal material SL. As a result, theliquid crystal material is sandwiched between the transparent substrateSUB1 and the transparent substrate SUB2 and enclosed with the sealmaterial SL. Thus, the seal material SL is formed as a portion thatencloses the liquid crystal material in a part thereof or a patternhaving no trace of the same, i.e., a continuous annular pattern.

A first rib-like supporting strut SPS1 is formed inside the sealmaterial SL and between the seal material SL and the liquid crystaldisplay area AR such that it substantially surrounds the liquid crystaldisplay area AR. That is, the first rib-like supporting strut SPS1 isprovided with an opening OP in a part thereof and is formed such that itsurrounds the liquid crystal display area AR, except at the opening OP.

A second rib-like supporting strut SPS2 is formed on the seal materialSL side of the first rib-like supporting strut SPS1 and in the vicinityof the opening OP. The second rib-like supporting strut SPS2 is not onlyformed in a region opposite to the opening OP of the first rib-likesupporting strut SPS1, but it is also formed with a length sufficient tocover, i.e. to extend across, the opening OP.

Therefore, the planar pattern defined by the first rib-like supportingstrut SPS1 and the second rib-like supporting strut SPS2 is formed suchthat an exit (opening OP) is provided in a part of the first rib-likesupporting strut SPS1 surrounding the liquid crystal display area AR andsuch that the exit leads to a passage that extends on the left and rightof the same and that is surrounded by walls constituted by the firstrib-like supporting strut SPS1 and the second rib-like supporting strutSPS2.

The first rib-like supporting strut SPS1 and the second rib-likesupporting strut SPS2 may be formed at the same time when strut-likespacers are formed to maintain a gap between the transparent substrateSUB1 and the transparent substrate SUB2 in the liquid crystal displayarea AR. As a result, an increase in the number of manufacturing stepsis avoided.

In such a case, for example, a layer made of resin is formed throughouteither of the substrates (SUB1 or SUB2), and the strut-like spacers, thefirst rib-like supporting strut SPS1, and the second rib-like supportingstrut SPS2 are simultaneously formed through selective etching utilizinga so-called photolithographic technique.

In such a configuration, the liquid crystal material LQ is dispensed tothe region surrounded by the first rib-like supporting strut SPS1, asshown in FIG. 2, to fill the region with the liquid crystal materialsuch that the liquid crystal display area AR is sufficiently covered.That is, the liquid crystal material can be dispensed without any directcontact occurring between the liquid crystal material and the sealmaterial SL.

In this case, the liquid crystal material may be dispensed in excess,such that a redundant portion of the liquid crystal material flows fromthe exit (opening OP) formed in the first rib-like supporting strut SPS1into the passage that extends on the left and right of the exit and thatis surrounded by walls constituted by the first rib-like supportingstrut SPS1 and the second rib-like supporting strut SPS2, the liquidcrystal being maintainable in that passage. It is therefore possible toavoid direct contact between the liquid crystal material and the sealmaterial SL also in this case.

Since the liquid crystal material will not directly contact contaminantsincluded on the seal material SL, the liquid crystal material can bealways kept free from any contaminant. This makes it possible to preventthe occurrence of irregularities of luminance attributable to suchcontaminants.

In a sense, the region where the liquid crystal material resides isautomatically optimized by the amount of the liquid crystal itself. Thismakes it possible to maintain the gap with stability.

Even when the liquid crystal panel is pressed from the outside to anextent that a change in the gap results, the redundant portion of theliquid crystal automatically adjusts the amount of the liquid crystal ineach region to an optimum value in accordance with changes in regionswhere the liquid crystal exists.

Thus, the seal material SL still functions as a seal material in that itisolates the liquid crystal from the outside, although the previousfunction of directly enclosing the liquid crystal material according tothe related art is eliminated.

A liquid crystal display device having such a configuration can bealways kept free from any contaminant because the liquid crystalmaterial therein does not contact contaminants included on the sealmaterial SL. This makes it possible to prevent the occurrence ofirregularities in luminance attributable to the contaminants.

Such a configuration is advantageous also in that it is possible tosuppress variations of the gap at the liquid crystal layer attributableto temperature changes. Specifically, it is known that a gap change of0.1 μm can be caused by a cubical expansion of the liquid crystalmaterial attributable to a temperature change from room temperature toan elevated temperature (in the range from 20° C. to 60° C.). In thiscase, since the liquid crystal material flows in the passage from theexit (opening OP) in the first rib-like supporting strut SPS1 in anamount corresponding to such expansion, it is possible to prevent theoccurrence of the gap change.

As shown in FIG. 3, the first rib-like supporting strut SPS1 may beprovided such that it is close to the seal material SL on the side wherethe video signal driving circuit He is provided and further from theseal material SL on the opposite side where the video signal drivingcircuit He is not provided.

One reason for this is that the liquid crystal display area ARsurrounded by the first rib-like supporting strut SPS1 can be located inthe middle of the transparent substrate SUB1 relative to the outer frameof the liquid crystal panel or the periphery of the transparentsubstrate SUB1 in the present embodiment. In other words, as seen inFIG. 3, the distance d1 from the peripheral edge of the transparentsubstrate SUB1, where the video signal driving circuit He is provided,to the seal material SL can be set to be substantially equal to thedistance d2 from the other peripheral edge, opposite to the peripheraledge of the transparent substrate SUB1 where the video signal drivingcircuit He is provided, to the seal material SL. Another reason for thisarrangement is that the second rib-like supporting strut SPS2 can beformed in a relatively large space on the opposite side where the videosignal driving circuit He is not provided.

Preferably, the passage that extends on the left and right of the exit(opening OP) formed in the first rib-like supporting strut SPS1 and thatis surrounded by walls constituted by the first rib-like supportingstrut SPS1 and the second rib-like supporting strut SPS2 has asufficiently great length. In order to suppress the spread ofcontamination of the liquid crystal material, it must be formed with alength greater than the width between the first rib-like supportingstrut SPS1 and the seal material SL on the side where the scan signaldriving circuit V is provided. Therefore, such a configuration may beemployed.

(Method of Enclosing the Liquid Crystal)

FIGS. 4A to 4D are diagrams which constitute a flow chart showing anembodiment of a method of enclosing a liquid crystal material betweeneither of the substrates (e.g., the transparent substrate SUB2) formedwith a first rib-like supporting strut SPS1 and a second rib-likesupporting strut SPS2 and the other substrate (e.g., the transparentsubstrate SUB1) provided opposite to that substrate, as described above.

Step 1 (FIG. 4A)

The transparent substrate SUB2 is prepared, the substrate having alreadybeen formed with the first rib-like supporting strut SPS1 and the secondrib-like supporting strut SPS2, and the seal material SL.

Step 2 (FIG. 4B)

A liquid crystal material LQ is dispensed to an area surrounded by thefirst rib-like supporting strut SPS1, i.e., a liquid crystal displayarea AR.

Step 3 (FIG. 4C)

The transparent substrate SUB2 is combined with the transparentsubstrate SUB1 in a face-to-face relationship in a low pressure orvacuum state.

Step 4 (FIG. 4D)

The transparent SUB1 and the seal material SL are secured together.

Second Embodiment

FIG. 5 is a plan view of another embodiment of a liquid crystal displaydevice according to the invention.

The configuration of this embodiment is different from that of FIG. 3 inthat an exit (opening OP) formed in the first rib-like supporting strutSPS1 and a passage extending on the left and right of the exit andsurrounded by walls constituted by the first rib-like supporting strutSPS1 and the second rib-like supporting strut SPS2 are formed also on aside where a video signal driving circuit He is provided.

As a result, when the liquid crystal material is dispensed, a redundantportion of the liquid crystal material can be sufficiently accommodated.

Third Embodiment

FIG. 6 is a plan view of another embodiment of a liquid crystal displaydevice according to the invention.

The configuration of this embodiment is different from that of FIG. 3 inthat a plurality of (two in the figure) exits (openings OP) formed inthe first rib-like supporting strut SPS1 and a plurality of (two in thefigure) passages extending on the left and right of the exits andsurrounded by walls constituted by the first rib-like supporting strutSPS1 and second rib-like supporting struts SPS2 are formed side by sideon the side opposite to the side where a video signal driving circuit Heis provided, for example.

It is obvious that such a configuration also makes it possible toaccommodate a redundant portion of the liquid crystal materialsufficiently when the liquid crystal material is dispensed.

Fourth Embodiment

FIG. 7 is a plan view of another embodiment of a liquid crystal displaydevice according to the invention and is an embodiment similar to thatof FIG. 6.

FIG. 7 is similar to FIG. 6 in that a plurality of (two in the figure)exits (openings OP) formed in a first rib-like supporting strut SPS1 anda plurality of (two in the figure) passages extending on the left andright of the exits and surrounded by walls constituted by the firstrib-like supporting strut SPS1 and second rib-like supporting strutsSPS2 are formed side by side on the side opposite to the side where avideo signal driving circuit He is provided. The main difference in thetwo embodiments lies in the fact that the second rib-like supportingstruts SPS2 of FIG. 6 are combined and formed continuously as a singlestrut in the embodiment of FIG. 7.

In such a configuration, the adjusting effect can be enhanced because adepressurized (vacuum) region is formed in the passages between theportions of the liquid crystal material that flow out from therespective exits.

Fifth Embodiment

FIG. 8 is a plan view of another embodiment of a liquid crystal displaydevice according to the invention.

The configuration of this embodiment is different from that of FIG. 3 inthat the exit (opening OP) formed in the first rib-like supporting strutSPS1 and the passage extending on the left and right of the exit andsurrounded by walls constituted by the first rib-like supporting strutSPS1 and a second rib-like supporting strut SPS2 are formed on the sideopposite to the side where the scan signal driving circuit V isprovided.

In this case, either of the first rib-like supporting struts SPS1 may beformed close to the seal material SL and the other strut may be formedfurther from the seal material SL in order to position the liquidcrystal display area AR (an area surrounded by the first rib-likesupporting strut SPS1) substantially in the middle of the outer frame ofthe liquid crystal panel or a transparent substrate SUB1 in a directionacross the scan signal driving circuit V (x-direction).

Sixth Embodiment

FIG. 9 is a plan view of another embodiment of a liquid crystal displaydevice according to the invention.

The configuration of this embodiment is different from that of FIG. 3 inthat a passage from an exit (opening OP) formed in the first rib-likesupporting strut SPS1, that is surrounded by walls constituted by thefirst rib-like supporting strut SPS1 and a second rib-like supportingstrut SPS2, extends only in one direction.

Specifically, the first rib-like supporting strut SPS1 and the secondrib-like supporting strut SPS2 have portions that are connected to eachother, and the passage extending in one direction from the exit isdefined by unconnected portions of the struts.

Seventh Embodiment

FIG. 10 is a plan view of another embodiment of a liquid crystal displaydevice according to the invention and is an embodiment similar to thatof FIG. 9.

The configuration of this embodiment is different from that of FIG. 9 inthat the passage extending in one direction from an exit (opening OP)formed in the first rib-like supporting strut SPS1 is extended also tothe side that faces a scan signal driving circuit V by extending thesecond rib-like supporting strut SPS2. In other words, the passageextending in one direction is formed such that it passes around a cornerof the first rib-like supporting strut SPS1.

Obviously, this makes it possible to provide a passage having a greatlength so as to be able to accommodate a greater amount of redundantliquid crystal material sufficiently when the liquid crystal material isdispensed.

Eighth Embodiment

FIG. 11A is a plan view of another embodiment of a liquid crystaldisplay device according to the invention, and FIG. 11B is a sectionalview taken along the line b-b in FIG. 11A.

FIGS. 11A and 11B show a case in which the first rib-like supportingstrut SPS1 and second rib-like supporting strut SPS2 are formedsimultaneously with strut-like spacers SP that are dispersed in a liquidcrystal display area AR.

The strut-like spacers SP are provided to maintain a gap between atransparent substrate SUB1 and a transparent substrate SUB2, so that thespacing therebetween is uniform, in order to make the thickness of aliquid crystal layer uniform.

All of the strut-like spacers, the first rib-like supporting strut SPS1,and the second rib-like supporting strut SPS2 may be made of a materialsuch as resin and may be formed simultaneously by selectively etching aresin layer formed throughout a surface of either substrate on a liquidcrystal side thereof using a photolithographic technique.

Ninth Embodiment

FIG. 12 is a sectional view which shows another embodiment of a liquidcrystal display device according to the invention.

The configuration of this embodiment is different from that shown inFIG. 11B in that a black matrix BM is formed on a surface of atransparent substrate SUB2 on the liquid crystal side thereof, forexample; the black matrix BM is formed such that it extends outward whenstrut-like spacers, as described above, are formed above the blackmatrix BM; and a first rib-like supporting strut SPS1 and a secondrib-like supporting strut SPS2 are formed in the extended portion.

The heights of the tops of the first rib-like supporting strut SPS1, thesecond rib-like supporting strut SPS2, and the strut-like spacers fromthe top surface of the transparent substrate SUB2 are made equal inorder to ensure tight contact between the tops of these members and thetransparent substrate SUB1.

Tenth Embodiment

FIG. 13 is a sectional view which shows another embodiment of a liquidcrystal display device according to the invention. FIG. 13 shows a statein which a transparent substrate SUB1 has not been overlaid yet.

The configuration of this embodiment is different from that shown inFIG. 12 in that a first rib-like supporting strut SPS1 and a secondrib-like supporting strut SPS2 are formed such that the height of thetop of each strut from the top surface of a transparent substrate SUB2is greater than the height of the top of each strut-like spacer SP fromthe top surface of the transparent substrate SUB2.

In this case, the above-described configuration may be provided byforming a certain layer (e.g., a color filter FIL) under the regionswhere the first rib-like supporting strut SPS1 and the second rib-likesupporting strut SPS2 are formed, while forming no such layer under theregion where the strut-like spacers are formed.

As shown in FIG. 14, any difference between the height of the tops ofthe first rib-like supporting strut SPS1 and the second rib-likesupporting strut SPS2 from the top surface of the transparent substrateSUB2 and the height of the tops of the strut-like spacers from the topsurface of the transparent substrate SUB2 is compensated by providing agap adjusting layer GAL on the surface of the transparent substrate SUB1facing the strut-like spacers SP.

In such a configuration, when liquid crystal material is dispensed onthe surface of the transparent substrate SUB2, since it tends to spreadwith the liquid level maintained on the same horizontal plane, thedispensing of the liquid crystal material can be completed with theliquid level kept lower than the height of the first rib-like supportingstrut SPS1 and the second rib-like supporting strut SPS2. When thetransparent substrate SUB1 is overlaid in a face-to-face relationship inthis state, a redundant portion of the liquid crystal material can beled to an exit (opening OP) of the first rib-like supporting strut SPS1and introduced into a passage. This makes it possible to avoid directcontact between the redundant liquid crystal material and the sealmaterial SL with reliability.

The effect of height adjustment in the present embodiment is not limitedto the case in which the struts SPS1 and SPS2 are continuous supportingstruts. It also works in a case in which the struts SPS1 and SPS2 areprovided discretely.

The same effect can be achieved by providing an overcoat layer OC on thefilter FIL, instead of the filter FIL, and shaping the overcoat layer OCsimilarly to the filter FIL of FIG. 13.

FIG. 15 shows the configuration of another embodiment of a transparentsubstrate SUB1. In this configuration, a gap adjusting layer GAL isformed on a liquid crystal side of the substrate such that it extendseven in a region where a second rib-like supporting strut SPS2 isformed, and the layer has openings at the locations of the firstrib-like supporting strut SPS1 and the second rib-like supporting strutSPS2.

Eleventh Embodiment

FIG. 16 shows the configuration of another embodiment of a liquidcrystal display device according to the invention.

The configuration of this embodiment is different from that shown inFIG. 3 in that both ends of a second rib-like supporting strut SPS2 areextended so as to surround the first rib-like supporting strut SPS1completely. In such a configuration, the passage from an exit (openingOP) of the first rib-like supporting strut SPS1 can be madesignificantly large, which also makes it possible to accommodate a greatamount of redundant liquid crystal material sufficiently when the liquidcrystal material is dispensed.

Twelfth Embodiment

FIG. 17 shows the configuration of another embodiment of a liquidcrystal display device according to the invention.

In particular, FIG. 17 shows a setting of dimensions of a first rib-likesupporting strut SPS1 and a second continuous pillar-like supportingstrut SPS2.

It has been experimentally confirmed that a setting expressed by d>10cis preferable, where the first rib-like supporting strut SPS1 has anarea of a×b, and where c and d (in the one side of a passage)respectively represent the width and length of a passage that is formedby walls constituted by the second rib-like supporting strut SPS2 andthe first rib-like supporting strut SPS1 on the left and right of anexit (opening OP) of the first strut.

Therefore, when the passage is formed on only one side of the exit(opening OP) of the first rib-like supporting strut SPS1, as shown inFIG. 9, it is preferable to set a relationship expressed by d>20cbetween the width c and the length d of the passage.

Each of the above-described embodiments may be used along or incombination with one another. The purpose is to allow the advantages ofeach embodiment to be achieved along or in combination with the others.

In the above embodiments, it is preferable to use a thermosetting sealmaterial as the seal material SL. One reason for this is that athermosetting seal material has a high bonding strength and is thereforesuitable for the formation of a large panel. Another reason is thatcontamination of the liquid crystal material attributable to such asealing material can be prevented according to the present invention.

As apparent from the above description, the invention makes it possibleto provide a liquid crystal display device in which the spread ofcontamination to the liquid crystal material is prevented.

1. A liquid crystal display device comprising: a pair of rectangularshaped substrates with liquid crystal material therebetween; a pluralityof first spacers formed on one of the pair of substrates; a secondspacer formed on the one of the pair of substrates, and arranged tosurround the plurality of first spacers in plane view; a seal materialformed between the pair of substrates, and arranged to surround thesecond spacer in plane view, the seal material being continuously formedalong each side of all sides of the rectangular shaped substrates sothat the seal material along one side connects with the seal materialalong an adjacent side; wherein the first spacers and the second spacerare made of resin; wherein a distance from the one of the pair ofsubstrates to a top surface of the first spacers is smaller than adistance from the one of the pair of substrates to a top surface of thesecond spacer; and wherein another of the pair of substrates has a gapadjusting layer so as to compensate for a gap resulting from adifference in the distance between the first spacers and the secondspacer with respect to the one of the pair of substrates.
 2. A liquidcrystal display device according to claim 1, wherein the first spacersand the second spacer have substantially the same thickness in adirection substantially parallel to a plane of the one of the pair ofsubstrates.
 3. A liquid crystal display device according to claim 1,wherein the gap adjusting layer is arranged at a portion correspondingto the plurality of first spacers.
 4. A liquid crystal display deviceaccording to claim 1, further comprising a third spacer formed on theone of the pair of substrates, wherein the second spacer is arrangedbetween the plurality of the first spacers and the third spacer in planeview, and a length of the third spacer is longer than a length of thefirst spacer in plane view.
 5. A liquid crystal display device accordingto claim 4, wherein the first spacers, the second spacer and the thirdspacer have substantially the same thickness in a directionsubstantially parallel to a plane of the one of the pair of substrates.6. A liquid crystal display device according to claim 5, wherein the gapadjusting layer is arranged at a portion corresponding to the pluralityof first spacers.
 7. A manufacturing method of liquid crystal displaydevice including the steps of: forming a plurality of first spacers, asecond spacer and a seal material on one substrate having a rectangularshape; forming a liquid crystal layer on the one substrate; combininganother substrate with the one substrate; wherein the second spacer isarranged to surround the plurality of first spacers in plane view;wherein the seal material is arranged to surround the second spacer inplane view, the seal material being continuously formed along each sideof all sides of the one rectangular shared substrate so that the sealmaterial alone one side connects with the seal material along anadiacent side; wherein a distance from the one substrate to a topsurface of the first spacers is smaller than a distance from the onesubstrate to a top surface of the second spacer; and wherein another ofthe pair of substrates has a gap adjusting layer so as to compensate fora gap resulting from a difference in the distance between the firstspacers and the second spacer with respect to the one of the pair ofsubstrates.
 8. A manufacturing method accordance to claim 7, wherein thefirst spacers and the second spacer are formed at substantially the sametime.
 9. A manufacturing method according to claim 8, wherein the gapadjusting layer is arranged at a portion corresponding to the pluralityof first spacers.
 10. A method according to claim 7, further comprisingthe step of forming a third spacer on the one substrate, wherein thesecond spacer is arranged between the plurality of first spacers and thethird spacer in plane view, and a length of the third spacer is longerthan a length of the first spacer in plane view.
 11. A manufacturingmethod according to claim 10, wherein the first spacers the secondspacer and the third spacer have substantially the same thickness in adirection substantially parallel to a plane view of the one substrate.12. A manufacturing method according to claim 11, wherein the gapadjusting layer is arranged at a portion corresponding to the pluralityof first spacers.
 13. A liquid crystal display device according to claim1, wherein the seal material enables sealing of the one of the pair ofsubstrates to the another of the pair of substrates and enclosing of theliquid crystal material between the pair of substrates.
 14. Amanufacturing method according to claim 7, wherein the seal materialenables sealing of the one substrate to the another substrate andenclosing of the liquid crystal layer between the one substrate and theanother substrate.